From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 796D0C2D0E4 for ; Tue, 24 Nov 2020 05:40:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 14591206FB for ; Tue, 24 Nov 2020 05:40:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="P3CIYtiI" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729075AbgKXFjv (ORCPT ); Tue, 24 Nov 2020 00:39:51 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45622 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728874AbgKXFjv (ORCPT ); Tue, 24 Nov 2020 00:39:51 -0500 Received: from mail-pf1-x449.google.com (mail-pf1-x449.google.com [IPv6:2607:f8b0:4864:20::449]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 363D0C0613D6 for ; Mon, 23 Nov 2020 21:39:51 -0800 (PST) Received: by mail-pf1-x449.google.com with SMTP id i124so3851395pfc.6 for ; Mon, 23 Nov 2020 21:39:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=WQ4ZxyeJ9Apc3xH1FaLNSteLy9y1Y4c/AILukn+NVIg=; b=P3CIYtiIkUOJoK4cjQtBDJidp31JrD7y30leztKJY3wb6rr+mtzf9hScrX30EjmEr8 Qc8UHg02EFnGV9w0X0BZ5/1bd4zup+sS4OY6IXZWgOUkwdkzwwLksU1CRkNRsPvsvQ4l NCmPfO9lTaFAfpO6KE1fiDfhyDJOVe+zTzrZMbeBPrxWCyhLpw2k/8Wyw0hxYqGDAPYO RlV5bnixU/kNyzEnPpemoQ1fjVr7l/sqQiCDShSZFofOf35wwmlL/AoUkNG3L0XB43Bq d1fe5lROpS5sxfUP5kZ0G31StDXoW4UmtmT4Glm6q4YmZ94Yns1nPHQ985blv2s0dqLD sMEw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=WQ4ZxyeJ9Apc3xH1FaLNSteLy9y1Y4c/AILukn+NVIg=; b=Tps2YzIpUd6/+XW8L44bQE/X66YYceGxjxytfkYJNjCkveqkOrn+96lJx8LfVxWnV5 1ucfN9peW0TARqDEb5kfyAnrVeKaeqbKRvIZSrDEOiGoBMDei3QkxceItXZ1cwHNx8KZ 6ceqMg/Xru/jteupgCHbiPK2FqAx1NGJZzlh9K4T4Cyq0PLdrGCKWMvfhIW8Gl1HHlaW mOa6sgDUP73EZ9Uhnd9BBYOZQoCgFpRB5Vqfwvwioa+kqoVuu3mEd0IOUeq5RSdLQQmJ DKBf+TMlAtEhN+OR42CYUOC4IlNbqKM6jxLMXPGmg98UPbc7da+ANCl4H7X6JE+eEVUP PKwQ== X-Gm-Message-State: AOAM533dC2zOsQlzdGMlr67w6ZnOvEF7lmdf5pyf6THsPgX4Nf5CAsJ1 gvPIp0qzBd6NM8D4p06HYlzkt9AOS2Q= X-Google-Smtp-Source: ABdhPJzYgYj0Gaa3zyqbP1lcIVQadsjt1/PvdBrTNvcUdNqNS2AyaWSXSbZ36FloPm6HS7wGQIlt6udxoLE= Sender: "surenb via sendgmr" X-Received: from surenb1.mtv.corp.google.com ([2620:15c:211:200:f693:9fff:fef4:2055]) (user=surenb job=sendgmr) by 2002:a17:90b:293:: with SMTP id az19mr426644pjb.1.1606196390299; Mon, 23 Nov 2020 21:39:50 -0800 (PST) Date: Mon, 23 Nov 2020 21:39:42 -0800 In-Reply-To: <20201124053943.1684874-1-surenb@google.com> Message-Id: <20201124053943.1684874-2-surenb@google.com> Mime-Version: 1.0 References: <20201124053943.1684874-1-surenb@google.com> X-Mailer: git-send-email 2.29.2.454.gaff20da3a2-goog Subject: [PATCH 1/2] mm/madvise: allow process_madvise operations on entire memory range From: Suren Baghdasaryan To: surenb@google.com Cc: akpm@linux-foundation.org, mhocko@kernel.org, mhocko@suse.com, rientjes@google.com, willy@infradead.org, hannes@cmpxchg.org, guro@fb.com, riel@surriel.com, minchan@kernel.org, christian@brauner.io, oleg@redhat.com, timmurray@google.com, linux-api@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@android.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org process_madvise requires a vector of address ranges to be provided for its operations. When an advice should be applied to the entire process, the caller process has to obtain the list of VMAs of the target process by reading the /proc/pid/maps or some other way. The cost of this operation grows linearly with increasing number of VMAs in the target process. Even constructing the input vector can be non-trivial when target process has several thousands of VMAs and the syscall is being issued during high memory pressure period when new allocations for such a vector would only worsen the situation. In the case when advice is being applied to the entire memory space of the target process, this creates an extra overhead. Add PMADV_FLAG_RANGE flag for process_madvise enabling the caller to advise a memory range of the target process. For now, to keep it simple, only the entire process memory range is supported, vec and vlen inputs in this mode are ignored and can be NULL and 0. Instead of returning the number of bytes that advice was successfully applied to, the syscall in this mode returns 0 on success. This is due to the fact that the number of bytes would not be useful for the caller that does not know the amount of memory the call is supposed to affect. Besides, the ssize_t return type can be too small to hold the number of bytes affected when the operation is applied to a large memory range. Signed-off-by: Suren Baghdasaryan --- arch/alpha/include/uapi/asm/mman.h | 4 ++ arch/mips/include/uapi/asm/mman.h | 4 ++ arch/parisc/include/uapi/asm/mman.h | 4 ++ arch/xtensa/include/uapi/asm/mman.h | 4 ++ fs/io_uring.c | 2 +- include/linux/mm.h | 3 +- include/uapi/asm-generic/mman-common.h | 4 ++ mm/madvise.c | 47 +++++++++++++++++--- tools/include/uapi/asm-generic/mman-common.h | 4 ++ 9 files changed, 67 insertions(+), 9 deletions(-) diff --git a/arch/alpha/include/uapi/asm/mman.h b/arch/alpha/include/uapi/asm/mman.h index a18ec7f63888..54588d2f5406 100644 --- a/arch/alpha/include/uapi/asm/mman.h +++ b/arch/alpha/include/uapi/asm/mman.h @@ -79,4 +79,8 @@ #define PKEY_ACCESS_MASK (PKEY_DISABLE_ACCESS |\ PKEY_DISABLE_WRITE) +/* process_madvise flags */ +#define PMADV_FLAG_RANGE 0x1 /* advice for all VMAs in the range */ +#define PMADV_FLAG_MASK (PMADV_FLAG_RANGE) + #endif /* __ALPHA_MMAN_H__ */ diff --git a/arch/mips/include/uapi/asm/mman.h b/arch/mips/include/uapi/asm/mman.h index 57dc2ac4f8bd..af94f38a3a9d 100644 --- a/arch/mips/include/uapi/asm/mman.h +++ b/arch/mips/include/uapi/asm/mman.h @@ -106,4 +106,8 @@ #define PKEY_ACCESS_MASK (PKEY_DISABLE_ACCESS |\ PKEY_DISABLE_WRITE) +/* process_madvise flags */ +#define PMADV_FLAG_RANGE 0x1 /* advice for all VMAs in the range */ +#define PMADV_FLAG_MASK (PMADV_FLAG_RANGE) + #endif /* _ASM_MMAN_H */ diff --git a/arch/parisc/include/uapi/asm/mman.h b/arch/parisc/include/uapi/asm/mman.h index ab78cba446ed..ae644c493991 100644 --- a/arch/parisc/include/uapi/asm/mman.h +++ b/arch/parisc/include/uapi/asm/mman.h @@ -77,4 +77,8 @@ #define PKEY_ACCESS_MASK (PKEY_DISABLE_ACCESS |\ PKEY_DISABLE_WRITE) +/* process_madvise flags */ +#define PMADV_FLAG_RANGE 0x1 /* advice for all VMAs in the range */ +#define PMADV_FLAG_MASK (PMADV_FLAG_RANGE) + #endif /* __PARISC_MMAN_H__ */ diff --git a/arch/xtensa/include/uapi/asm/mman.h b/arch/xtensa/include/uapi/asm/mman.h index e5e643752947..934cdd11abff 100644 --- a/arch/xtensa/include/uapi/asm/mman.h +++ b/arch/xtensa/include/uapi/asm/mman.h @@ -114,4 +114,8 @@ #define PKEY_ACCESS_MASK (PKEY_DISABLE_ACCESS |\ PKEY_DISABLE_WRITE) +/* process_madvise flags */ +#define PMADV_FLAG_RANGE 0x1 /* advice for all VMAs in the range */ +#define PMADV_FLAG_MASK (PMADV_FLAG_RANGE) + #endif /* _XTENSA_MMAN_H */ diff --git a/fs/io_uring.c b/fs/io_uring.c index a8c136a1cf4e..508c48b998ee 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -4118,7 +4118,7 @@ static int io_madvise(struct io_kiocb *req, bool force_nonblock) if (force_nonblock) return -EAGAIN; - ret = do_madvise(current->mm, ma->addr, ma->len, ma->advice); + ret = do_madvise(current->mm, ma->addr, ma->len, ma->advice, 0); if (ret < 0) req_set_fail_links(req); io_req_complete(req, ret); diff --git a/include/linux/mm.h b/include/linux/mm.h index db6ae4d3fb4e..414c7639e394 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2579,7 +2579,8 @@ extern int __do_munmap(struct mm_struct *, unsigned long, size_t, struct list_head *uf, bool downgrade); extern int do_munmap(struct mm_struct *, unsigned long, size_t, struct list_head *uf); -extern int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in, int behavior); +extern int do_madvise(struct mm_struct *mm, unsigned long start, unsigned long len_in, + int behavior, unsigned int flags); #ifdef CONFIG_MMU extern int __mm_populate(unsigned long addr, unsigned long len, diff --git a/include/uapi/asm-generic/mman-common.h b/include/uapi/asm-generic/mman-common.h index f94f65d429be..4898034593ec 100644 --- a/include/uapi/asm-generic/mman-common.h +++ b/include/uapi/asm-generic/mman-common.h @@ -80,4 +80,8 @@ #define PKEY_ACCESS_MASK (PKEY_DISABLE_ACCESS |\ PKEY_DISABLE_WRITE) +/* process_madvise flags */ +#define PMADV_FLAG_RANGE 0x1 /* advice for all VMAs in the range */ +#define PMADV_FLAG_MASK (PMADV_FLAG_RANGE) + #endif /* __ASM_GENERIC_MMAN_COMMON_H */ diff --git a/mm/madvise.c b/mm/madvise.c index a8d8d48a57fe..1aa074a46524 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -1001,6 +1001,14 @@ process_madvise_behavior_valid(int behavior) } } +static bool can_range_madv_lru_vma(struct vm_area_struct *vma, int behavior) +{ + if (!can_madv_lru_vma(vma)) + return false; + + return true; +} + /* * The madvise(2) system call. * @@ -1067,15 +1075,21 @@ process_madvise_behavior_valid(int behavior) * -EBADF - map exists, but area maps something that isn't a file. * -EAGAIN - a kernel resource was temporarily unavailable. */ -int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in, int behavior) +int do_madvise(struct mm_struct *mm, unsigned long start, unsigned long len_in, + int behavior, unsigned int flags) { unsigned long end, tmp; struct vm_area_struct *vma, *prev; int unmapped_error = 0; int error = -EINVAL; + int error_on_gap; int write; - size_t len; + unsigned long len; struct blk_plug plug; + bool range_madvise = !!(flags & PMADV_FLAG_RANGE); + + /* For range operations gap between VMAs is normal */ + error_on_gap = range_madvise ? 0 : -ENOMEM; start = untagged_addr(start); @@ -1123,13 +1137,14 @@ int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in, int beh blk_start_plug(&plug); for (;;) { /* Still start < end. */ - error = -ENOMEM; + error = error_on_gap; + if (!vma) goto out; /* Here start < (end|vma->vm_end). */ if (start < vma->vm_start) { - unmapped_error = -ENOMEM; + unmapped_error = error_on_gap; start = vma->vm_start; if (start >= end) goto out; @@ -1140,10 +1155,18 @@ int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in, int beh if (end < tmp) tmp = end; + /* For range operations skip VMAs ineligible for the behavior */ + if (range_madvise && !can_range_madv_lru_vma(vma, behavior)) { + prev = vma; + goto skip_vma; + } + /* Here vma->vm_start <= start < tmp <= (end|vma->vm_end). */ error = madvise_vma(vma, &prev, start, tmp, behavior); if (error) goto out; + +skip_vma: start = tmp; if (prev && start < prev->vm_end) start = prev->vm_end; @@ -1167,7 +1190,7 @@ int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in, int beh SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior) { - return do_madvise(current->mm, start, len_in, behavior); + return do_madvise(current->mm, start, len_in, behavior, 0); } SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec, @@ -1183,7 +1206,7 @@ SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec, size_t total_len; unsigned int f_flags; - if (flags != 0) { + if (flags & ~PMADV_FLAG_MASK) { ret = -EINVAL; goto out; } @@ -1216,12 +1239,21 @@ SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec, goto release_task; } + /* + * For range madvise only the entire address space is supported for now + * and input iovec is ignored. + */ + if (flags & PMADV_FLAG_RANGE) { + ret = do_madvise(mm, 0, ULONG_MAX & PAGE_MASK, behavior, flags); + goto release_mm; + } + total_len = iov_iter_count(&iter); while (iov_iter_count(&iter)) { iovec = iov_iter_iovec(&iter); ret = do_madvise(mm, (unsigned long)iovec.iov_base, - iovec.iov_len, behavior); + iovec.iov_len, behavior, flags); if (ret < 0) break; iov_iter_advance(&iter, iovec.iov_len); @@ -1230,6 +1262,7 @@ SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec, if (ret == 0) ret = total_len - iov_iter_count(&iter); +release_mm: mmput(mm); release_task: put_task_struct(task); diff --git a/tools/include/uapi/asm-generic/mman-common.h b/tools/include/uapi/asm-generic/mman-common.h index f94f65d429be..4898034593ec 100644 --- a/tools/include/uapi/asm-generic/mman-common.h +++ b/tools/include/uapi/asm-generic/mman-common.h @@ -80,4 +80,8 @@ #define PKEY_ACCESS_MASK (PKEY_DISABLE_ACCESS |\ PKEY_DISABLE_WRITE) +/* process_madvise flags */ +#define PMADV_FLAG_RANGE 0x1 /* advice for all VMAs in the range */ +#define PMADV_FLAG_MASK (PMADV_FLAG_RANGE) + #endif /* __ASM_GENERIC_MMAN_COMMON_H */ -- 2.29.2.454.gaff20da3a2-goog